1. Field of the Invention
The present invention is related to a receiver applied to a satellite down converter and a radio frequency metal-oxide-semiconductor amplifier, and particularly to a receiver applied to a satellite down converter and a radio frequency metal-oxide-semiconductor amplifier capable of changing a resonant frequency thereof with a usage band.
2. Description of the Prior Art
In the prior art, when a satellite down converter receives a signal of a satellite microwave band (a C band, an X band, a KU band, or a Ka band), operation range of an amplifier of the satellite down converter has to cover the whole satellite microwave band, that is, the operation range of the amplifier is very large, resulting in difficulty in designing a proper amplifier applicable to the satellite down converter. Please refer to FIG. 1A. FIG. 1A is a diagram illustrating a radio frequency metal-oxide-semiconductor amplifier 100 applied to the satellite down converter according to the prior art. As shown in FIG. 1A, the radio frequency metal-oxide-semiconductor amplifier 100 includes an N-type metal-oxide-semiconductor transistor 102 and an inductor 104. Parasitic capacitors of the inductor 104 and the radio frequency metal-oxide-semiconductor amplifier 100 can determine a fixed resonant frequency ω of the radio frequency metal-oxide-semiconductor amplifier 100. Please refer to FIG. 1B. FIG. 1B is a diagram illustrating a frequency response of the radio frequency metal-oxide-semiconductor amplifier 100. As shown in FIG. 1B, because operation range of the radio frequency metal-oxide-semiconductor amplifier 100 has to cover the satellite microwave band and maintain proper gain flatness, the radio frequency metal-oxide-semiconductor amplifier 100 has a lower Q value, lower power efficiency, and worse image rejection, resulting in a designer of the satellite down converter facing difficulty in designing the radio frequency metal-oxide-semiconductor amplifier 100 to operate properly over all potential bands.